The successful operation of certain rotating machines such as hot kilns has, in the past, proved difficult to sustain. Due to wear and tear of the supporting bearings and tires, and distortion of various parts of the system, including possible movement of the supporting piers upon which the kilns are mounted, the bearing rollers can get out of alignment, so as to cause portions of the kiln to rotate about different rotational axes. These motions then produce cyclic distortions of the kiln shell. Such cyclic distortions adversely affect the meshing of the driving gears and can become disruptive of production and destructive of the kiln lining and the shell.
In my earlier U.S. Pat. No. 5,148,238, issued Sep. 15, 1992, I disclosed the use of a diode laser instrument for making accurate measurements to the surface of the kiln shell, in determining the location of its centre of rotation at that position. The laser measurements for each axial station along the length of the shell were made at three cardinal locations about the shell, in a plane normal to the kiln main axis, and the points of measurement indexed back at the instant of measurement to a pair of datum axes running alongside the length of the kiln, close to ground level. In the working environment of an operating kiln the extended time necessary to effect the necessary operations, including instrument relocations, at the three o'clock, six o'clock and nine o'clock positions, and the difficulty of locating the instrument at those locations all combine to make the operation tedious and time consuming.